- 1
A vertex is a corner point — the exact spot where two lines or edges meet. A triangle has three vertices; a square has four; a cube has eight. The word is mostly a maths word, and you will meet it in geometry class more than anywhere else. Note the plural: teachers usually say *vertices* (VER-ti-seez), though *vertexes* is not wrong.
A vertex頂點 is a corner point是一個角的交點 — the exact spot where two lines or edges meet也就是兩條線或兩個邊相交的那個確切點。A triangle三角形 has three vertices有三個頂點；a square正方形 has four有四個；a cube立方體 has eight有八個。The word這個字 is mostly a maths word主要是個數學用字，and you而你 will meet it in geometry class more than anywhere else在幾何課上最常遇到它。Note the plural注意複數：teachers老師 usually say *vertices* (VER-ti-seez)通常說 vertices（唸作 VER-ti-seez），though *vertexes*不過 vertexes is not wrong也不算錯。
In maths it has a second, related job: the vertex of a (that U-shaped curve) is its turning point, the very bottom of the U or the very top of the upside-down U.
In maths在數學裡 it這個字 has a second, related job還有第二個相關的用法：the vertex of a parabola (that U-shaped curve)拋物線（那個U形曲線）的頂點 is its turning point是它的轉折點，the very bottom of the U or the very top of the upside-down U也就是U形最底部，或倒U形最頂端的那一點。
Outside maths, the word is rare and rather technical. Doctors use it for the very top of the head, and in computer graphics a vertex is one of the points that make up a 3D model — game designers talk about how many vertices a character has. In ordinary talk, people just say *corner* or *point*; if you said "the vertex of the table", it would sound strange, almost like a joke.
Outside maths在數學以外，the word這個字 is rare and rather technical很少見而且相當專業。Doctors醫生 use it for the very top of the head會用它來指頭頂的最高點，and而 in computer graphics在電腦繪圖裡 a vertex一個頂點 is one of the points that make up a 3D model是組成3D模型的其中一個點——game designers遊戲設計師 talk about how many vertices a character has會討論一個角色有多少個頂點。In ordinary talk平常說話，people大家 just say *corner* or *point*就直接說 corner 或 point；if you said "the vertex of the table"如果你說 "the vertex of the table"（桌子的頂點），it它 would sound strange, almost like a joke聽起來會很奇怪，簡直像在開玩笑。
組成From Latin *vertex*, which first meant a whirl or a spinning eddy of water, then the crown of a swirl — the top of your head where the hair spins around — and from there simply the highest point, a summit. So the idea travelled: spin → the top of the spin → the top of anything.
原始詞典資料11 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
vertexnoun/ˈvɜː.tɛks/
- 1
The highest point, top or apex of something.
- The mountain’s vertex was covered in snow.
- He reached the vertex of his career after decades of work.
- 2
anatomymedicinesciencesThe highest point, top or apex of something.
- 3
geometrymathematicssciencesAn angular point of a polygon, polyhedron or higher order polytope.
- 4
geometrymathematicssciencesAn angular point of a polygon, polyhedron or higher order polytope.
- 5
mathematicssciencesA point on the curve with a local minimum or maximum of curvature.
- 6
graph-theorymathematicssciencesOne of the elements of a graph joined or not by edges to other vertices.
- 7
computer-graphicscomputingengineeringA point in 3D space, usually given in terms of its Cartesian coordinates.
- 8
engineeringnatural-sciencesopticsThe point where the surface of a lens crosses the optical axis.
另外 3 個記錄的用法
- 9
natural-sciencesphysical-sciencesphysicsAn interaction point.
- 10
astrologyhuman-sciencesmysticismThe point where the prime vertical meets the ecliptic in the western hemisphere of a natal chart.
- 11
mediapublishingtypographyA sharp downward point opposite a crotch, as in the letters "V" and "W" but not "Y".
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。